1. Field of the Invention
The present invention relates to curable polymers. More specifically, the present invention relates to ambient temperature-curable compositions containing water-borne epoxy-containing vinyl addition polymers.
2. Brief Description of the Prior Art
Self-curable compositions comprising amino-containing polymers and epoxy functional polymers are known in the art. There has been great difficulty in keeping these compositions from reacting prematurely. Hence, there has been a concern with pot life and stability of these compositions, and consequently, much work has been expended with film properties of these compositions in improving these compositions to these ends.
One solution to the problem of premature reaction entails capping the reactive amino groups with, say, ketones to form a ketimine prior to mixing the amine-containing polymers with the epoxy-containing polymer. After the coating is applied, atmospheric moisture causes the ketimine to decompose yielding reactive amino polymers which co-react with the epoxy-containing polymer to effect cure. There are two main drawbacks to this type of composition. First, it is limited to non-aqueous systems and second, the ketone is released upon cure, thus causing environmental pollution problems.
Another solution to the problem comprises using amino and epoxy-containing polymers which are water-insoluble. To reduce solvent pollution, there are employed lower viscosity amino and epoxy-containing polymers in admixtures that require little or no solvent or the use of water as the solvent.
In the case of the solvent-based compositions, molecular mixing brings the reactants into immediate contact, thus precipitating premature reaction. In the case of the water-based compositions, the amino and epoxy-containing polymers are emulsified separately and blended just before application. Generally, the individual emulsified polymers consisting of many individual molecules are not stabilized enough to prevent coagulation with each other. Compositions containing these emulsified polymers are therefore not sufficiently stable.